Combination Radiofrequency Ablation and Vertebral Cement Augmentation for Spinal Metastatic Tumors: A Systematic Review and Meta-Analysis of Safety and Treatment Outcomes

Background The treatment of spine metastases continues to pose a significant clinical challenge, requiring the integration of multiple therapeutic modalities to address the multifactorial aspects of this disease process. Radiofrequency ablation (RFA) and vertebral cement augmentation (VCA) are two less invasive modalities compared to open surgery that have emerged as promising strategies, offering the potential for both pain relief and preservation of vertebral stability. The utility of these approaches, however, remains uncertain and subject to ongoing investigation.This systematic review and meta-analysis evaluates the available evidence and synthesize the results of studies that have investigated the combination of RFA and VCA for the treatment of spinal metastases, with the goal of providing a comprehensive and up-to-date assessment of the efficacy and safety of this therapeutic approach. Methods A literature search was conducted using the electronic databases PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and Scopus from their inception to May 4th, 2022 in accordance with PRISMA guidelines. Studies were included if they met the following criteria: 1) spine metastases treated with RFA in combination with VCA, 2) available data on at least one outcome (i.e., pain palliation, complications, local tumor control), 3) prospective or retrospective studies with at least 10 patients, and 4) English language. Meta-analyses were conducted in R (R Foundation for Statistical Computing; Vienna, Austria), using the meta package. Results In the 25 included studies, a total of 947 patients (females = 53.9%) underwent RFA + VCA for spinal metastatic tumors. Out of 1163 metastatic lesions, the majority were located in the lumbar region (585/1163 [50.3%]) followed by thoracic (519/1163 [44.6%]), sacrum (39/1163 [3.4%]), and cervical (2/1163 [0.2%]). 48/72 [66.7%] metastatic lesions expanded into the posterior elements. Preoperative pathologic vertebral fractures were identified in 115/176 [65.3%] patients. Between pre-procedure pain scores and post-procedure pain scores, average follow-up (FU) was 4.41± 2.87 months. Pain scores improved significantly at a short-term FU (1-6 months), with a pooled mean difference (MD) from baseline of 4.82 (95% CI, 4.48-5.16). The overall local tumor progression (LTP) rate at short-term FU (1-6 months) was 5% (95% CI, 1%-8%), at mid-term FU (6-12 months) was 22% (95% CI, 0%-48%), and at long-term FU (>12 months) was 5% (95% CI, 0%-11%). The pooled incidence of total complications was 1% (95% CI, 0%-1%), the most frequent of which were transient radicular pain and asymptomatic cement extravasation. Conclusion The findings of this meta-analysis reveal that the implementation of RFA in conjunction with VCA for the treatment of spinal metastatic tumors resulted in a significant short-term reduction of pain, with minimal total complications. The LTP rate was additionally low. The clinical efficacy and safety of this technique are established, although further exploration of the long-term outcomes of RFA+VCA is warranted.